1. Field of the Invention
The present invention generally relates to customer pole displays which are referred to as point-of sale pole displays or pole displays, commonly used in Point-of-Sale (POS) systems, and more particularly to providing power to point-of sale pole displays without requiring connection to an alternating current power source.
2. Background of the Related Art
A customer pole display is a common peripheral device used with most point-of-sale (POS) terminals. A major function of the pole display is to show the customer retail transaction information, such as an identification or description of the item being purchased, the quantity being purchased, the corresponding unit price, the total price, and the like. In many states, the inclusion of a pole display in a POS terminal is required by law.
The current most popular method to interface a pole display to a computer, in cases where the POS application software is installed, is through an RS232 port. FIG. 1 shows a conventional pole display assembly 10 with an RS232 interface connector 12. However, since the RS232 interface does not provide sufficient power to energize a pole display, a power adaptor 14 is required to step down the 120VAC or 240VAC power obtained from a standard electrical outlet to about 7VAC, which is then rectified and regulated in the pole display assembly 10 to 5VDC. The power adaptor is shown as being attached to a pigtail cable connected to the RS232 interface connector 12.
FIG. 2 shows a block diagram of the conventional pole display assembly 10 with RS232 interface shown pictorially in FIG. 1. Display data and commands from the POS computer terminal enter into the pole display assembly 10 through the RS232 interface connector and an RS232 interface circuit 16. A microcontroller 18 processes the data and commands from the RS232 interface circuit 16 and transmits this information to a vacuum fluorescent display (VFD) 20 to illuminate appropriately addressed display pixels.
Most commercially available VFDs require two special voltages; approximately 4.7VAC for filament power and approximately 40VDC for anode power. These two voltages are ordinarily generated by a DC-DC converter 22. As indicated above, the primary source of power for the pole display assembly 10 is conventionally derived from the AC power line connected to the power adapter 14. The power adapter 14 steps down the line voltage to approximately 7VAC and an AC rectifier and voltage regulator 22 converts the 7VAC voltage to a stable 5VDC voltage, which is used to power the RS232 interface 16, microcontroller 18, and DC-DC converter 24. However, the array of peripheral connectors and electronics is costly, cumbersome, difficult to assemble, and subject to failure.
Thus, there is a need in the field of POS computer terminals for an alternative that would alleviate the need for a pigtailed external power adapter that reliably converts 120VAC power to the voltages required by the pole display assembly associated with a POS computer terminal and the corresponding peripheral components and electronics.